Intel Corp. is close to a deal to buy Israeli chip company Tower Semiconductor Ltd. for nearly $6 billion, according to people familiar with the matter, in its latest move to bolster a plan to make more chips for other companies.

A deal could be unveiled as soon as this week, assuming the talks don’t fall apart, the people said. The deal would likely include a hefty premium, given Tower’s market value of roughly $3.6 billion; indeed, the shares soared more than 50% in after-hours trading on Monday after The Wall Street Journal reported on the expected takeover.